Electbic exchange system



. T. BROWN.

ELECTRIC EXCHANGE SYSTEM.

APPLICATION FILED AUG. 16, 1921.

Reissued Jan. 10, 1922.

- INVENTOR mafia-173 v A. T. BROWN.

ELECTRIC EXCHANGE SYSTEM.

APPLIPATION FILED AUG. 16. 192i,

Rgissued Jan. 10, 1922. 15,261

8 SHEETS-SHEET 2.

A. T BROWN.

ELECTRlC EXCHANGE SYSTEM.

AllL-ICAHQN \FILED AUG; m, 192'.

15,26 1: SHEETS-SHEET s.

RFissued Jun; 10, 1922.

INVENTQR A. I. BROWN.

ELECTRIC EXCHANGE SYSTEM.

APPLICATION FILED AUG. I5. I921. Reissued Jan. 10, 1922, 15,261,

3 SHEETS-SHEET 4.

. INVENTOR I A. T. BRUWN.

ELECTRIC EXCHANGE SYSIEM.

APPLICATION FILED AUG. 16. l92l Reiasucd Jam. 10, 1922. 15,261";

a SHEETS -SHEET 5.

INVENTOR A. T.- BROWN.

ELECTRIQ EXCHANGE SYSTEM. APPLICATION- mzo AUG. 16, 921.

Reissued J an. 10, 1922.

e" e I INVENTOR manderl'LBrou/m A. T. BROWN.

ELECTRIC EXCHANGE SYSTEM.

APPLICATION min AUG.I6. 1921.

Reissued Jan. 10, 1922. 15,261.

8 SHEETS-SHEET 7- INVENTOR ruierIBrvwm A. T. BROWN.

ELECTRIC EXCHANGE SYSTEM. APPLICATION FILED AUG. 16. 1921.

SHEE1,'261.

Reissued' Jan. 10, 1922.

UNITED s'mres PATENT OFFICE.

ALEXANDER T. BRO N, OE SYRACUSE, NEW YORK, ASSIGNOR, BY MEsNEv ASSIGN- MENTS, '10 sTRoMBERe-cARLsON TELEPHONE MANUFACTURING COMPANY, OF ROCHESTER, NEW YORK, .11 CORPORATION OF NEW YORK.

ELECTRIC EXCHANGE SYSTEM.

Specificationof Reissued Letters Patent. Rei d J o 1 Original NO. 992,333, datedMay 16, 1911, Serial No. 550,933, filed May 28,1595. Renewed July 16, 1910,

Serial No. 572,282.

T all whom it may concern Be it known that I, ALEXANDER T. BROWN,

of S mouse, in the county of Onondaga, in

, taken in connection with the accompanymg drawing, is a full, clear, and exact description.

had to the accompanying drawing, forming a partof this specification, in which like letters and numerals indicate corresponding parts in all the views.

Figure 1 is a diagrammatic view illustrating the general constructlon and arrangement of an electric exchange systemembodying my invention. Fig. 2 is an elevation partly in section, of one of the detached switching apparatus of the system, shown in its normal position. Fig. 3 is an elevation, partly in section, of the switching apparatus seen in Fig. 2, which is here shown in operative position. Fig. 4 is adetail section taken online 4-4, Fig. 3. Fig. 5 is a face view of'one of the controlling devices of the systern, its indicators being shown in their position'assumed for effecting the movement of .tliecorresponding switching apparatus to the position assumed by the switching ap; p'aratus in Fig. 3. Fig. 6 is a face yiew of the controlling device seen in Fig. 5, 1ts indicators being illustrated in a different position from that assumed in Fig. 5. F1 Tis a horizontal section, taken on line 7 Fig. 5. Fig. 8 is a vertical section, taken oniline 8-8, Fig. 7 Figs. 9 and 10are'vertical sections looking in opposite directions, taken respectively on lines 99 and 10.10,

My invention relates to improvements in Application for reissue'filed August 16, 1921 Serial NO. 492,852.

Fig. 8. Fig. 11 is a detail section, taken on line 1111, Fig. 7. Fig.-12 is a top plan view. of the brushes or terminals of one of the controlling devices, and the terminal support for engaging said brushes or terminals shown diagrammatically as a fiat-plate. F lgs. 1,3 and 14 are detail sections, taken, respectively, onlines 13-13 and 14'14, Fig. 6. Figs. 15 and 16 are detail sections, taken respectively on lines 15-.15 and 16 16, Flgs. 11 and 8; and Fig. 17 is'a detall elevation of 'a part of an index suitable for use wlth my improved system. i

In my improved electric exchangesystem, eachcircuit for which automatic connection is desired is provided witha switching apparatus for connecting the same with the other c rcuits, and a controlling devicefor governing the passage of the current over the circuit and'thereby controlling or effectmg the operation Of the switching apparatus. Both the switching apparatus and the controlling device are preferably of substantlally the construction herein illustrated and described, although either may be used illustrated only three switching apparatus and a correspondingnumber of connected circuits. It requires however, but sli ht changes in the "construction of the switching apparatus and controllingdevices torender 'the'same capable of operation in connection with a system having a greater number of circuits than 900.

The separate circuits converge at a common or main station, are each provided with at least one subscribers station and preferably consists of two line conductors or wires which are so connected by a common conductor, ross connections, switching apparatus,

and controlling devices that a metallic circuit is established between any two connected circuits for securing substantially undis turbed intercommunication. The adjacent ends of the line conductors or wires of the separate circuits, their main or common conductor, and the cross connections are preferably so arranged and the switching apparatus so constructed, that a movable terminal for connecting the corresponding circuit with another circuit is required to move but a minimum distance. To facilitate this result each switching apparatus is provided with a series of terminals the number of which is a submultiple, and preferably the square root, of the number of the separate circuits. Each switching apparatus is also preferably utilized to cooperate with the controlling device of the circuit connected by said'switching apparatus to the circuit leading therefrom for insuring absolute S8' crecy between the two connected circuits. It 1s obvious however, that each sw1tch1ng apparatus may be provided with but a single movable terminal and may be constructed without those features tending to secure secrecy between the connected circuits. In the operation of the switching apparatus, I also preferably avail myelf of the same line con:

ductors or wires used for communication between the circuits, and thus reduce the expense of w1r1ng; and when the system contains a large number of circuits, I prefer to use both conductors or wires of each circuit for effecting or controlling the operation of the respective switching apparatus. To facilitate this result the opposite ends of both of the line conductors orwires of the circuits are connected to the ground either normally or at intervals, although it is obvious, that instead of using the ground as a conductor additional wires may be substituted without materialdeparture from this invention As my present system is particularly applicable for use with a large number of circuits some of which will necessarily be comparatively long, I prefer to actuate the switching apparatus by a suitable motor and to merely govern the movement of each switching apparatus by thecorresponding controlling device; but it is apparent that instead of usingga' separate motor for effecting the operation of the switching apparatus, a magnet maybe connected directly to each switching apparatus for (producing this movement. A A B B C represent suitable conductors or wires of a series of circuits, converging at a main or common station D, and provided with subscribers stations A 13 G a b c automatic switching apparatus at the station D connected to the adjacent ends of said conductors; and D a main or common conductor at the station D connected to each of said switching apparatus and connected by a conductor or wire D to a suitable source of electric energy as a dynamo D ductors or wires A? A, B B, C G which i will be referred to in describing the con-- trolling devices The conductors or wires A B C are provided with fixed contactterminals A B G arranged preferably in parallel at themain or common station I), and the switching apparatus a b c are formed with movable terminals a a a 79 21 and I,

0 c 0 which contact with said fixed terminals and are mounted on suitable supports a b 0 forming parts of the respec-- tive switching apparatus a b 0. The fixed contact-terminals preferably extend longi tudinally across the paths of all of the movable terminals of the switching apparatus, but it is obvious that each circuit may be provided with a separate fixed terminal for each switching apparatus. Said fixed contact-terminals A B C may consist of separated Wires or, as illustrated, of comparatively thin bars separated by suitable insu-v lation d. i

Suitable cross conductors A. B C extend from the fixed contact-terminals A B C and may connect directly to their respective circuit conductors A 3 C although in order to aid in insuring secrecy when two circuits are connected, these cross conductors A B C terminate at circuit breakers A B C which are connected by conductors (ir Wires A B?" C to said circuit conductors A B C and are operated by the respective switching apparatus, a b 0, as presently described Each switching apparatus is here shown as provided with a plurality of movable terminals, and consequently each movable terminal engages only a limited number of the fixed contact-terminals, and if desired the first terminal of the series engaged by one of the movable terminals'may be slightly separated from the last terminal of the se-.

ries engaged by the next adjacent movable terminal, as illustrated at Figs. 2 and 3,

although this arrangement is not essential.

The number of the movable terminals of each switching apparatus preferably equals the square rootof the number of the circuits of the system, but the number of said movable terminals may be'either greater or less than said square root although it should be a submultiple of the total number of said circuits, The switching apparatus here illustrated being designed for. use with 900 electric circuits, is therefore preferably provided with 30 movable terminals, and the fixed contact-terminals of the circuits are divided into 30 series each containing theterminals of 30 circuits. I have not deemed it necessary or advisable to illustrate either the entire number of fixed contact-terminals,

' two entire series of 30 fixed contact-terminals and two movable terminals a a of the switching apparatus as presently described, suitably separated from each other for engaging the fixed terminals of each of said series. and movable terminals of myelectric exchange system are arranged similar to the like terminals previously referred to, and the terminal support of each switching apparatus isrequired to move only as far as any one of its movable terminals. It is obvious however that if the switching apparatus are each provided with a greater or less number of movable terminals, that their terminal supports will be required to move a less or greater distance.

The switching apparatus of my exchange system are all of the same construction and in order to simplify the description of this invention I will specifically describe only the one a. The terminal support a of said apparatus (1 preferably consists of a reciprocating insulating bar or strip formed with cutouts a for receiving the movable terminals a a of, &c., which are electrically connected by a suitable conductor as a bar or strip (1 secured to said support a and connected to the movable conductor A. It is desirable that the terminals a a a may move independently, and they are therefore preferably secured to the conductor a by conducting pivots a and are normally held out of operative position against the action of springs a arranged in the cutouts a. The means for holding the movable terminals out of operative position preferably consists of pins or rods a", moved lengthwise in apertures or guides in the support a by a reciprocating rack a presently described, which is provided with cutouts a arranged one in advance of "the other for permitting the springs a to successively force said pins or rods into inoperative position and to successively force the movable terminals a a a into their plane of engagement with the fixed terminals A? B C. The pins or rods a preferably engage the movable terminals a a a but electrical connection between said parts is prevented by insulators a The remaining fixed side of the support a and is movable independently thereof in the'direction indicated by arrow 1, Fig. 3, by a suitable feed controlled by an electrically operated mechanism connected to the circuit leading to the switching apparatus a'and composed of the line conductors or wires A A Theterminal support a, and the rack a may be suitably vided with guides 03 d for preventin transverse-movement of the rack 01 T e support ais provided with projecting arms a which engage the opposite faces of the rack a and prevent lateral movement of said support, and if desired, a tongue and groove connection between the adjacent edges of said support and rack, or suitable guide pieces-or bars, not necessary to herein illustrate, may be used to prevent a lateral movement of the support a. v

The feed for the rack a may be of any desirable construction but it preferably consists .of a feeding dog a, a suitable stop as a dog a, a motor D and suitable connections between the feeding dog and the motor. The feeding dog a is arranged at the 1 outside of the rack andis pivoted at a to a suitable support a which may be provided with ears a for guiding the racka and is mounted on the main conductor or common conductor D consistin preferably 1 5 of. a spindle or pivotal pin. K spring a normally forces the free end of the feeding dog toward the rack a, but a. pin a? secured to the support a and movable in a slot a in the feeding dog, normally prevents the engagement of said dog and rack. The pin a and the slot a connect the feeding dog tothe support or" with a lost motion .at a point between the pivot a and the free end of the dog, and this connection 5 enables the feeding dog to swing onits pivot when engaged with the rack a ,'imti-l the pin a reaches the opposite end of the slot e whereupon the support a holds said dog firmly in engagement with the rack and prevents undue lfeeding thereof. The supporta is reciprocated to and fro,

as presently described, and each forward movement operates the dog a to feed the rack o a single tooth or step. The stop or dog on prevents return movement of the rack a and is preferably mounted on the conductor or spindle D andinormally engaged with the rack a by a suitable spring a; v 30 The motor D for'operating the feed for the rack m may be of any desired form, size, and construction, and the support a may .be suitably connected thereto. "In the preferableform ofmy invention, the motor D consists of a constantly oscillating shaft which is provided with a lengthwise shoulder (Z and is actuated by any suitable mechanism not necessary to herein illustrateor describe. The connection between said motor and the support a preferably consists of a movable arm at having one end pivoted at a to the outer end of the support a and its opposite end movable into engagement with theshoulder d As the arm a is engaged with the shoulder d, as presently described, the support a" is rocked on the conductor or spindle D in the direction shown by arrow 2, Figs. 2 and 3, against the action of a spring a and operates the feeding dog a to advance the rack a" a single tooth. The spring a then operates to return the support a" and gravity is utilized to facilitate said movement and to hold the arm a in its normal position, since I preferably arrange the terminal support a and the rack a in a vertical plane. It is obvious however that if the parts a a fare otherwise arranged a suitable spring may be utilized to return the arm 00 The electrically operated mechanism for connecting the feeding dog support with the motor D may be of any desirable form, size, and construction, but it preferably. con sists of a magnet a in circuit with the con ductor or wire A, and a lever a pivoted to asuitable support a and having one end connected by a link a to the armature of said magnet and its opposite end engaged with the movable arm a, for forcing the same into engagement with the shoulder 61 of the motor D. As will be presently described, the passage of the current through the magnet 11 is governed by a suitable controlling device e, but in order that the op eration of the switching apparatus may be positively assured, a suitable circuit breaker is connected to the line conductor or wire A in proximity to the switching apparatus a for breaking the circuit through said conductor at each movement of the rack a and the break in said circuit is utilized to advance the operating pieces of the controlling device, presently described, which regulate the operation of said controlling device. Any suitable circuit breaker may be used for this purpose, and I have here illustrated one of simple construction consisting As the-feeding dog support a is moved onwardly from its normal position for advancing the rack 0 a single step; the upper end of said support is separated from the terminal a and the circuit through the line conductor or ,wire A is thus broken until said support assumes its normal position in engagement with the terminal a; whereupon a current may be again passed" through the line conductor or wire A for engaging the arm a, with the motor D and thereby effecting a second advance movement of the rack a)". Consequently, as the break in the circuit through the conductor or wire A, is dependent upon each movement of the rack a and the movement of the operating pieces of the controlling device e, presently described, which regulate the operation of said controlling device is dependent upon each break of the circuit through the conductor or wire A, it is obvious that the magnet 03 remains energized for connecting the feeding dog support with the motor D until said parts are connected and the feeding dog support commences its onward movement. Moreover, no additional current pulsation is passed through the conductor or wire A for operating the switching apparatus a until the support a is in its normal position and again restores the circuit through the line conductorv or wire A. a

The rackrt is moved lengthwise as described until the desired-movable terminal of the corresponding support a has been forced into operative position, whereupon the rack is connected by any suitable mechanism to said support a for moving the same lengthwise until said movable terminal engages the desired fixed contact-terminal. Said connecting mechanism preferably consists of a magnet a connected in circuit with the line conductor or wire A a connecting dog a pivoted to one or both of the ears a of the support a and movable into engagement with the rack a and a stop or dog a for normally holding the connecting dog out of operative position,

The magnet a may be connected to the grounded main conductonDby any suitable means, but I have here shown said magnet as connected thereto by a wire a, the feed ing dog support a", and conducting springs a a e interposed between said wire and support. The wire 0, is suitably connected to, the spring a, which is normally engaged with the spring a.- The. spring a is'suitably secured to the spring a and its free end is engaged by the outer endof the feeding dog support a", when'in its advance position as seen at Fig. 3. The spring a tends to move outwardly from engagement with the spring a, Figa 3, but is normally held in position for engaging said spring a by one of the arms a 'of the terminal support a. Upon the first onward movement of the terminal support a the spring a moves outwardly to its inoperative position and is not again established until the-return of said support to it's normal position, as presently described. A spring a is utilized to force the'connecting dog a into engagement with the rack a and a link a of considerable length is interposed between the stop dog a and the armature of the magnet a. As the magnet a is energized, the stop or dog a is withdrawn from operative position and the connecting dog a is engaged with the racka by the spring a, whereupon the support a is fed to the desired position by said rack. During this movement of the support a, the stop or dog a tis held outwardly on its pivot for preventing stoppage of the support by the link a.

As previously described, the rack a permits the movable terminals to assume their operative position, is connected to the support a as soon as the desired movable terminal is in operative position, and moves the support a from its normal position until said movable terminal is in engagement with the desired fixed contact-terminal. The terminal support a, as previously stated, is provided with thirty movable terminals, which are so arranged that when one first assumes operative osition it is separated one step from the rst terminal of the adjacent series of fixed contact-terminals. Consequently, to engage the first movable terminal a of the'support (1* with the first one" of the adjacent series of fixed contactterminals, it-requires one movement of the feed for the rack a to permit the terminal a to assume its operative position and a second movement of said feed to engage the terminal a with said fixed contact-terminal.

It, therefore, requires sixty movements of switching apparatus a and the corresponding v controlling device 6 are, however, preferably of such construction, that after the desired communication through said connected cir-- cuits has been secured, the controlling device e operates to permit the passage of electric current pulsations through the magnet a? until the rack a has passed beyond its position assumed when connecting the circuit leading from the switching apparatus a with the nine hundredth circuit. This additional movement of the rack m which preferably consists of two advances or steps is utilized to effect automatic return of said rack and the support a, to their normal posi-' tion. To permit of, this result a shoulder a secured to said rack, and thus connected to the terminal support a, engages an operating piece a of suitable construction for forcing the stop w from operative position. The automatic return by gravity of the support and rack a1. a is thus permitted and may be accelerated by weighting said parts. The operating piece a; is of suitable construction,,but preferably consists of a reciprocating bar guided in the cross bar a? and having one end provided with a shoulder arranged in the path of the shoulder a, and its opposite end provided with a cam face a for engaging an arm upon the stop a I and rocking said stop on the conductor or of operative position and is therefore provided with a notch a for receiving a corresponding tooth provided upon said stop.

As the rack a assumes its normal position, a suitable shoulder a thereon forces the operating piece at out of operative position and'the stop a is again engaged with said rack by the spring a". When rack a reaches the normal, its upper shoulder causes dog a to disengage the teeth of rack (L10 and to be held disengaged by locking dog a. Support a is thus unlocked from rack a It is very desirable to secure secret com munication between two connected circuits and although this result may be effected by various'means, I preferably utilize for its accomplishment the switching apparatus of one of said circuits and the controlling device of the other. When a switching apparatus connects its corresponding circuit witlranother, the terminal support of said switching apparatus is moved away from itsnormal position and breaks the circuit from its fixed contact-terminal. The current for connecting. two circuits must' be passed through the fixed terminal of the called station and thence through the line conductor or wire normally connected thereto, and when the circuit from the fixed contact-terminal of a station is broken, it is impossible to connect with said circuit.

As will be apparent after the description of the operation of the controlling devices of my electric exchange system, the terminal support of the controlling device of a connected or called circuit is forced from its normal position when the circuits are con nected for telephonic. or other communication, and thus prevents the operative connection of the telephone or other communicator of an additional circuit seeking conmotion with said called circuit. It is thus obvious that secret communication between two circuits is effected by the switching appanatus of one and the controlling device of trated but three switching apparatus a b c,

I have shown but three of the circuit breakers A? B C previously mentionedf In or der that the construction of said circuit breakers and the operation ofthe respective switching apparatus necessary for actuating the circuit breakersmay be readily appar; ent, I will now proceed to describe the circuit'breaker connected, to the switching apparatus a. This circuit breaker A may be of. any desirable form, size,iand construction, but it preferably consists ofa contact piece secured to one end of the cross conductor A and normally contacted with-the conductor a which is electrically connected to the movable conductor A Conse quently, when the support a is in its normal position the conductors A A are connectedby said circuit breaker and the cur rent is free to pass from the cross conductor A over the conductor A to the line conductoror wire A As soon as the support a moves from its normal position for connecting ,one. of its movable terminals v with the fixed contact-terminal of another circuit,the conductor a is disconnected from i the circuit'breaker A and the circuit from the fixed contact-terminal A through the cross conductor or wire A to the line conductor A is broken, and, even though a circuit should be connected with said fixed contact-terminal, it would be. cut ofl from com- ."municationrwith' the line conductor or wire f the connection of any additionalb'lrcuit thereto, but'asthe detail-construction and arrangement of the partsof the controlling devices of my system have not yet been described, the operation of the controlling device for effecting this result will be subse g quently pointed out. 55

As previously stated, the switching apparatus b careof the same construction as the apparatus a, and at Fig. 1 I havediagram matically shown movableterminals 72 b 0 c a, terminal supports 1) c, racks 6 0 feeding dogs I) 0 stops or'dogs 32 0,

"supports b" '0", arms 6 0 magnets b 6 b 0 and circuit breakers B C corresponding to the like parts a a a a a a a, a, 23 G26 (Z32, 2? (Z29 il) 30 36 (L33 34, 42, A9 f the switching apparatus 5.

The switching apparatus a b c are ar ranged side by side and the motor I) preferably extends crosswise thereof as seen by dotted lines at Fig. '1, in order that it may operate all of said apparatus. The con ductor D also preferably extends crosswise of the switching apparatus a b c and forms both a main or common electric conductor therefor, and a support or spindle for the feedingand stop dogs of their respective feed mechanisms. It is obvious however that a separate motor may be used for each switching apparatus and that any other suitable ma1n or common conductor may be utilized for connecting said switching ape f g which are all of the same construction,

and, in order to additionally simplify the description of this invention, I will describe only thecontrolling device 6 for the circuit leading from the station A". This controlling device consists of a suitable supporting frame 6 aseries of fixed brushes or terminals e e c e e, a movable terminal support 6', movable operating pieces a e for automatically operating the terminal sup port e 'escapements for controlling the movement of said terminal support'and operating pieces, and an actuating piece 6 for moving the terminal support.

The fixed brushes or terminals 6 e e e c are of suitable. form, size, and construction, are preferably arranged one alongside of the other and are securedto any desirable support e projecting from the rear wall of the frame 6 .The terminal support e is provided-with suitable terminals 6 -6 6 e e 6 e for engaging the former terminals 6 e e e e, and in-orderthat rotary motion may be utilized for effecting contact of said terminals, the support 6 preferably consists of a drumrmounted on a spindle a connected to a suitable grounded conductor or .wire 6: The terminals 6 e e e are electrically connected to the spindle e in anysuitable manner, as by contact, and the terminals 6 e 6 which may bedesignated as surface terminals, are insulated from St1d-Sp1nd'le.,

device 6 when suitahly for making connection with a desired circuit i and during this operation the terminal support c is revolved for varying the engagement of the terminals 6 a e e e, e e e e e e" 6 The mechanism for revolving the support 6 may be of any suitable form, size, .and construction, although it preferably consists of a spring, an escapementfor permitting the operation pf the spring, and

operating pieces 6 e", an actuating piece e and a. magnet 43 for operating the escapement. As clearly seen at Fig. 1, the line conductors or wires A A terminate at the fixed brushes or terminals e e; the conductors A A, previously mentioned, respectively connect the brushes or terminals 6? e to the lie conductor A and the terminal 6 and a conductor or wire 6 connects the brush or terminal 6 to the line conductor A. As previously stated, the telephones or other communicators A and the magnets of the signals A are connected in circuit with the conductors or Wires A A, and a second magnet a and the magnet e are respectively connected in circuit with the conductors or Wires AA for controlling the escape ments which govern the advance movement of the operating pieces 6 e and the terminal support 6. The magnet 6 may be formed of wire of high resistance as German silver, for reducing the amperage of the current passed through the conductor or wire A when the signals of two connected circuits are operated, but I preferably use for such purpose-a separate resistance e connected in circuit with the conductor A. This resistance 6 usually consists of an electric lamp which is arranged in proximity to the telephone or other communicator A andis particularly useful for guiding a subscriber to said telephone when darkness obscures its locality.

The terminal support 6 is preferably so arranged when in its normal or initial position that the terminals 6 e are in contact, and a current for operating the signal A is thus free to pass from a calling circuit over the conductors or wires A A to the grounded wire e, and in its passage illuminates the electric lamp 6 and energizes the magnet of the signal A. Said current also energizes the magnet e and tendsto move its armature which is connected to operate the escapement forv the terminal support c, but as willbe afterward explained, the armature of the magnet e is prevented from movement at this time and cannot operate said escapement. The telephone or other communicator A is arranged in close proximity to the controlling device e and normally restrains the actuating piece 6 presently described, from operative position. When the signal A is operated as described, by a calling circuit, the" subscriber removes the telephone A from'its normal position and the actuating piece e reversely rotates the terminal support 6 until the surface terminals e engages the fixed brushes or terminals e e and connects the telephone A in metallic circuit with the line conductors A A This reverse movement of the terminal support 0" breaks the normally grounded circuit through the terminals 6 e" and the conductor c and, as presently described, thereby controls the connection of the telephone to the line conductors or wires of the calling circuit.

WVhen the controlling device e is utilized to operate the. switching apparatus a for connecting another circuit with the conductors A A the operating pieces e 6?, are first placed in the desired position, and a suitable' spring for actuating the operating pieces is tensioned. as presently described. The terminal support 6 is then permitted to make its first advance or step in the direction indicated by arrows 3. Figs. 1, 9. 12, for separating the terminals 6 e and engaging the terminals 6 6 thus disconnecting the ground from the line conductor A and connecting the same to the line conductor A which is provided with the magnet 6 previously mentioned. The controlling device 6 then operates automatically to effect onward movement of-the rack a of the switching apparatus a, for permitting the desired movable terminal of said apparatus to assume its operative position, as previously described; and 'upon each advance of said rack, the circuit through the conductor A is broken and the armature of the magnet e is actuated to permit the advance of the operating pieces e 6 The movement of the rack a and the operating pieces 6 6 continues until the operating piece 6 reaches its operative position whereupon it permits a second advance or step of the terminal support e for connecting the terminals 6 e and thereby grounding the line conductor A This second advance movement of the ter minal support e is, however, not sufiicient to disconnect the terminals 6 e and thus break the round connection for the line conductor as the terminal 6 is of corn siderable' length.

Immediately after the second advance or step of the support a, the feeding dog support a" engages the terminal a and a current is free to pass from the main station D through the line conductor A for connecting the rack a of the switching apparatus a to the terminal support 0; as previously described, The controlling device 0 then continues to advance. the rack a after its connection to the support (1*, until the operating piece 6 permits the support a to make a third advance or step for disconnecting the terminals 6 e, e e andfconnecting the terminals 6 e e. The signal A is then connected in circuit with the line conductors, the current passing from conductor A through conductor 6 fixed terminal e mov able terminal a of the support 6 fixed terminal e conductor A to the conductor A, and the current from the main station D passes from the line conductor A through the controlling device 6 and the line con-' ductor A to the movable terminal or the switching apparatus a inoperative position,

and thence through the fixedcontact -terminal A of the connected or called circuit andthe normally grounded line conductor leading ffrom said, contact-terminal as will be hereinafter described. In its passage through said line conductors, the current energizes the magnet e ,'.operates the signal A and energizes and operates the corresponding magnet and signalof the connected circuit.

Upon the operation of the signal of the called circuit the subscriber of said circuit removes his telephone or other communimcator from its normal position, whereupon the terminal support of the adjacent controlling device is reversely moved for'connecting said telephone to both of the corresponding line conductors or wires and breaking the ground from said controlling device. The signals of the connected circuits then cease their'o'peration and the mag- 1 net e is deenergized whereupon the ter- ,minal support 6 is permitted to make a mon or main conductor D and the switching apparatus a.

After the desired communication has been obtained, the telephones or other communicators of the connected circuits are again returned to their normal position, thereby. causing the reversely moved term nal support of the called circuit to assume itsnormal position and permitting a fifth advance or step of the support 6 for connecting the terminals 6 6 The circuit from the main station'D is then free to pass through the line conductor A to the grounded conductor e", and consequently the rack a and the operating pieces a e continuefto advance until the limit of their movement is reached. The last advance movement of the rack a is utilized to return said rack and the ter minal support a to their normal position and, during the corresponding movement of the operating pieces '6 e", a third operating (piece a permitsthe sixth and last advance or step of the terminal support -e", forfseparating the terminals .e" e and engaging the terminals e e. The engagement 'of the thus controls the I lopssage of currents from the main station through the line co-n ductors or'wiresA A for operating theswitching apparatus a and thecontro'lling device 6. I

The terminals 6 6, e 6 e e e are preferably mounted on a revoluble drum and .will be unnecessary. I may also prefer to perate the signals of two connected circuits by some other current than the one passing from the main station D through both line conductors of the calling circuit and thenormally grounded line conductor of the called circuit, and' in thatevent, the terminal e maybe dispensed with. It is also obvious that providing these changes are made. in theswitching apparatus a and the terminals of the controlling device 6, it may be advisable to somewhat vary the arrangement and engagement of the remaining terminals of' said controlling device. Moreover, the mag nets 6 6 ma be connected to the terminal support 6 an the operating pieces 6 6 so as to directly effect the movement of said parts instead of operating escapements to permit suitable springs to accomplish this result.

As previously outlined, a rotary drum or terminal support, operating pieces, magnets, an actuating piece, and escapements are utilized to effect the desired engagement of the terminals of the controlling device 6, and althoughsaid parts may be'of any suitable form, size, and construction, and'may be connected in any desired manner, I will now proceed to briefly describe their preferable construction and connections. The drum '6 is loosely mounted'on the spindle e and is revolved thereon by, a spiral spring e having its opposite ends secured to said drum and spindle, Fig. 15. One end of the spindle e is journaled in the rear wall of the supporting frame 6 and its opposite end in a gear 6 having its hub ournaled in thesupporting wall 0 of the frame e.

are mounted on a suitable pivot e and the ZLII'IISG are fixed to a rocking shaft 6 provided With an arm 2 One of the arms 6 is preferably utilized as the armature for the magnet 6 previously referred to, and a suitable spring a normally separatessaid armature arm. 6 from the pole pieces of the magnet e thereby permitting the main escapement dog 6 to rock into engagement with the adj acent' tooth of the wheel a for port 6 and holding the secondary escapepreventing onward movement of the sup# ment dog 6 out of engagement with said v wheel a. The arms e are rocked from their normal position by the lever which tensions the main driving spring of the controlling devi'ce e, the operating pieces e 6 e and the magnet 6 and are returned to their normal position by the spring 6 When the arms 6 are moved against the action of the spring a the main escapement dog 6' is forced out of operative position and the secondary escapement dog 6 permits a slight onward movement of the drum 0 and then prevents its further movement. As the spring e returns the arms 6 the dog 6 is withdrawn from operative position and the support 6 continues the balance of its onward advance or step, until the dog e engages the tooth next adjacent to that previously engaged thereby.

The operating pieces a e 'Figs. 13 and 14: may be'of any desirable form, size, and construction, and are capable of assuming a number of different positions in which they are securely held by any suitable means as a support or disk 6 which rotates said operating pieces and engages the same with the arm 6 for rocking the shaft e and the arms e and thereby operating the escapement for the drum 6 to permit the second and third advances or steps thereof. Said operating pieces are preferably secured to indicators or hands e which facilitate their adjustment and are preferably pivoted upon the outer end of the spinde 6 The free ends of the indicators or hands 2 e are provided with suitable bearings e in which the operating pieces a e are reciprocally movable, and the support or disk 6 is preferably formed with a series of apertures e for receiving the inner ends of said operating pieces. The apertures e are preferably arranged in a circular series and as the controlling device 6 is designed for use with a raclra capable of making 62 steps I preferably use 61 apertures. The. operatthe support or disk e ing pieces a e are free to enter 60 of these apertures and'thusassume 60 different positions but one of the apertures is preferably closed by the operating piece 6 It is obvious however, that if the 1st and 60th apertures are suitably separated and the operating piece 6 is interposed between the same, the 61st aperture may be dispensed with and the operating piece 6 otherwise secured to In order that the operating pieces a e may be readily placed in the desired position the front wall of the frame 6 is. provided with 'a suitable indi-,

cator 6 consisting of graduations normally alined with the apertures e and when the indicators or hands e e are directly alined with two of said graduations the operating pieces 6 e are free to enter the correspond ing apertures e and are in the'deslred pos tion for effecting the movement of the terminal support 6 necessary to connect the de-' sired circuit to the conductors A A In order to utilize the controlling device 6 for actuating the switching apparatus a to connect any desired circuit with the line con-' ductors A A it is necessary to place both of the operating pieces 6 e in their designed position and consequently each circuit of my exchange system is designated by a-combina tion indicator, which may consist of two separate indicators composed of numerals, letters or other characters arranged in suit able combination for permitting the desired distinction between said indicators.

1 preferably use numerals for forming the indicators for the separate circuits, and at Fig. 17 I have shown a suitableindex or sheet H as'provided with combination indicators k 72 if, if, k [2, for representing the respective circuits leading to the stations A B C The subscribers forthese stations may be John Jones, James Jackson, and Jacob Johnson, and the indicators for the circuits leading from said stations preferably consist of the following combinations 1 2-, 2-3, 3-11. At Figs. 3 and 5, I have shown the switching apparatus a and the controlling device 6. in their positions as,- sumed when connecting with the line conductors A A the circuit represented by the combination indicator 3-11. Consequently, the movable terminal a is shown at Fig. 3, as engaged with the eighth contact-terminal 8/C of the series engaged by said movable terminal, and the operating pieces a e are shown at Fig. 5, as arranged in'the third and eleventh apertures e of the support or disk e. The line conductor A? is preferably connected to the first contact-terminal A of the series engaged by the movable terminal a and as the contact-terminals engaged by the 30 movable terminals of the switching apparat'u's a are. preferably numbered consecutively, it requires eleven advances or steps of thera-ck an and the operating pieces a e to connect the line conductors A A with the grounded conductor ofthe 68th clrcuit, which is provided with thefixed contact- .terminal 8/0, and is designated by the com.- bination indicator 311.

end of the spring e is fixed to the rear wall of the frame 6 and its opposite end is secured to a downwardly extending toothed arm c fixed to the-leeve e and engaged depending arm 6 is fixedto the spindle e and its free end detachably engages a shoulder projecting from the arm at, in order that the spindle and sleeve @1 e -=Imay move simultaneously in one, direction, and independently in the opposite direction. The free end of the spindle e projects beyond the front wall of the frame e and is provided wit-h a lever e, which is normally arranged in its position assumed at Figs. 5

and 6.

The lever a is tilted upwardly after the operating pieces 6 e are suitably arranged for calling a desired circuit, and is then returned to its normal position. As the lever e is tilted upwardly the arm a engages the arm 6 and moves the same against the action of the spring 6 until a suitable stop e limits the onward movement of the arm The spring 6 is thus tensioned and the arm 6 is restrained from return movement by the escapement for the support or disks. The movement of the arm 6 effected by the lever 6 is, however, sufficient to completelyrevolve the gear e meshing therewith, and thus detachably engage a tooth e projecting from said gear with a movable dog e secured to the support or disk e. The tooth e, and the dog 6 are so constructed and arranged, that the gear 6 when actuated bythe-arm e isfree to i move in the same direction as indicated by arrow 3, Fig. 10, without rotating the support or disk 6 and is afterward prevented from returning to its normal position, except when the escapement for the support or disk 6 permits the operating pieces a e to continue their onward movement as effected by the spring 6 After the gear 6 has been completely revolved, as described, and

has commenced its return movement, the lever 8? is prevented from again revolving said gear inthe same direction as that indicated by arrow 3, Fig. 10' until the terminal support 6 has made a complete revolution. The means for preventing such movement of the gear 6 may be of any desired form, size, and construction, but it preferably consists of a pivoted stop a, which engages the teeth, of the gear (3 and is forced out of engagement withisaid gear when the terminal support elis inits normal position, by a cam a secured to said terminal support.

After the lever e is tilted upwardly as described for tensioning the spring a, it is returned to its normal position, and this movement of .the lever e from and to its normal position is utilized to actuate the escapement for the terminal support 6 and thus permit the first advance or step of said support. This result may be accomplished by anysuitable'mechanism, but I preferably use the springsand arms e a? secured respectivelyto the sleeve (2 and the spindle e. As the lever at is tilted upwardly the arm a engages the arm 6, and rocks the escapement dogs e 6 in one direction, and as the lever e is reversely tilted said escapement dogs are moved in the opposite direc- The arm 6 just described is engaged escapement for the terminal support a is not actuated to permit an advance or step of said support. This stop may had any desirable form, size, and construction, but it preferably consists of an arm 6 fixed to the arm e and normally engaged with the arm a, Fig. 10.

The escapement for controlling the movement of the operating pieces e e", preferably consists of a toothed wheel a and escapement dogs 6 e actuated by the magnet 6 The wheel a is supported on a shaft provided with a pinion e meshing with gear teeth formed upon the periphery of the support or disk a and the escapement dogs 6 e are of any suitable construction capable of permitting successive step by step movements of the wheel a. As here illustrated, the dogs 9 e resemble the ordinary escapement dogs of a typewriter carriag'e, and one dog 6 is fixed to the arma ture of the magnets and the other dog a is pivoted to said armature. As the magnet a; is energized, the dog 6 is withdrawn from operative position and the wheel 6 completes an advance movement or step, and is restrained from further movement by the dog 6 The magnet e is then deenergized and the armature therefor is returned to its normal position by a suitable spring, thus engaging the dog 6 with the tooth of the wheel a, previously engaged by the dog 6 As the shaft providedwith the wheel 6 is geared to the support or disk carrying the operating. pieces 6 6 said operating pieces are permitted to make an advance movement or step upon each movement or step of the wheel a.

The switching. apparatus a and the controlling device 6 are preferably of such construction that their s'ynchronism is always maintained, but I have. deemed it advisable represented by the. indicators or hands 6 6 This adjustment is effected by securing the toothed escapement wheel a to a sleeve 6 the operating pieces 6 e have reached the desired adjustment effected by disengaging the wheel 6 from the dog a, as I preferably arrange an indicator or scale 6 upon the outer face of the support or disk 6 The graduations of the indicators e e are preferably similar and when the controlling device 6 is in its normal position, corresponding graduations of both indicators are in alinement with each other. In order that this adjustment of the operating pieces of the controlling device 6 may be readily apparent I have shown the indicators 6 e at Fig. 6 in their position assumed when the line conductors A A are connected with the circuit represented by the combination indicator 214:0, and it .will be noted. that the graduation 40 of the indicator 6 is alined with the graduation 0 of the indicator e. If, upon communicating with the subscriber of the circuit then connected to the line conductors A A it should be ascertained that the circuit represented by the combination indicator 21'41 was connected to the line conductors A A the user of the controlling device e would then withdraw the toothed escapement wheel 6 from engagement with the dog a, and rotate the support'or disk 6 until the graduation 41 of the indicator 6 was alined with the graduation Oof the indicator 6, whereupon the synchronism of the switching apparatus a and controlling device 6 would be established, and, upon the return of the support or disk 6 to its normal position the corresponding graduations of the indicators 6 a would be alined with each other.

The actuating piece 6 may be of any desirable form, size, and construction, and is preferably utilized to control the electric connection of the telehpone or communicator of a calling circuit desiring communication with the station A?, and also to permit the terminal support 6 to make its fifth advance or step for effecting the return movement of the switching apparatus a after it has been utilized to connect another circuit wlth said station A The actuating piece (2 preferably consists'of a lever suitably pivoted to the frame 6 and in order that the desired movements of the terminal support 6 may be effected thereby, it is provided withvupwardly projecting arms 6 e suitably secured thereto. The arm 6 is utilized-to reversely move the terminal support e and is normally arranged directly beneath aprojection or tooth 6 formed or provided upon said terminal support. The telephone or communicator A is normally engaged with the outer end of the actuating piece 6 and its weight depresses said actuating piece against the action of a spring 6 As the telephone A is removed, when a call is directed to the signal A, the actuating piece 6 is immediately elevated by the spring 6 thus engaging thearm e with the projection or tooth e and reversely moving the terminal sup ort e against the action of the spring 6 s previously stated, this movement of the terminal support connects the telephone A in circuit with the line conductors A' A and deenergizes the magnet of the calling circuit which governs the movement of the terminal support of the controlling device of said circuit; but, as soon as the telephone A is replaced in its normal position, the spring a returns the terminal support 6 to its initial position and the signal A is again in circuit with the line conductor A When the'controlling device 6 has operated to connect another circuit with the conductors A A and the magnet e has been 'deenergized by the removal of the telephone of the called circuit, the terminal support a has been permitted to make fourv advances or steps for connectin the telephone A to the line conductors A and at Fig. 9, I- have shown said terminal support in this position. The telephone A is thenmoved from its normal position upon the cessation of the operation'of the signal A,

and the spring 6 elevates the actuating 'rection.' After the desired communication has been obtained through the conductors A A and the circuit connected therewith, the

telephone A is again placed in its normal position, and the actuating piece 6 is depressed against the action of the spring 6 The spring ,6 then moves the spindle e"? to its normal position for rocking the escapement dogs 6 e in the opposite direction, and permitting the terminal support e? to make its fifth advance or step and ground the conductor A. The rack a of the switching device a then continues its onward movement, and after each advance or step thereof, the support or disk 6 carrying the operating pieces 6*" e is also advanced by the passage ofcurrent pulsations through the magnet e As the supporter disk 6" reaches its position immediately preceding its last advance or step, the operating piece 6 is in position to engage the arm 6 projecting from the spindle 6 During this last advance or step, the arm e is rockedupwardly and is immediately permitted to return to its normal position upon the action of the spring a, thus permitting the last advance or step of the terminal support 6 whereupon the ground is connected to the "of operative position by a shoulder 6 upon said support which is provided with a fiat-r tened portion 6 that permits the arm a to assume its operative position. As the connection of the telephone of the calling circuit is dependent upon the removal of the telephone of the called station from its normal position, it is obvious that if the" subscriber for said circuit is absent when permit this movement of the dogs 6 6 the end of the arm 6' normally engaged with said dogs is suitably cut away and to prevent undue movement of the support a suitable stop arm 9 on the lever e enters a groove or cut-out in said support, and

limits its movement. This groove or cutout is only alined with the arm e when the terminal support 6 is in its position assumed for engaging the terminal 6 with the fixed brushes or terminals e e and permitting thepassage of a signaling current through the line conductors A A When the terminal support 6 is in any other position, the stop arm 1 engages said support a and prevents the movement of the lever a" necessary for forcing the dogs e 6? from operative position. It will also be understood that the movement of the support 6 effected by the lever e is suflicient to disengage the terminals 6 e e, and engage the terminals 6 c and that is is impossible for said support to stop its advance movement when the terminal 6 is engaged I with the fixed brushes or terminals 6, e and thus connect the telephone A to the line conductors A At. As previously stated, the

controlling devices 7" g are of-the same construction as the controlling device 6, and at Fig. 1 I have diagrammatically shown fixed g, terminal supports f g, movable termig 9 conductors f f ,g g, magnets f f, 9 g, and resistance devices f 9 corresponding to the likeparts e e e e e" The controlling devlces c f g are important parts of my improved electric exchange system, and in order that they may be thoroughly understood, 1' will now briefly de scribe the steps of the operation of the con- .trolling device 6 and the circuits through said device for each operation thereof. \Vhen the controlling device 6 1s 1n its normal positlon, a calllng current from a station desiring to communicate with the subscriber at the station A is free to pass over the conductors or wires A A, the terminals 6 6 the spindle 6 and the conductor or wire a to the ground, and in its passage energizes the electric lamp 6, the ma net of the signal A, and the magnet e uring the passage of said current, the stop 6 prevents rocking of the spindle e by the arm a, which forms the armature of the magnet e and would otherwise be attracted thereby, and consequently, said magnet and the spring 6 do not operate'the escapement dogs 6 e and permit an advance or forward step of the support 6 Upon the operation of the signalA by said calling current, the subscriber removes the telephone A from the actuating piece 6 whereupon'the spring 6 elevates said actuating piece, and the arm 6 engages the tooth e! upon the terminal support e and reversely moves said support against the action of the spring a,

thereby engaging the surface terminal 6 with the fixed brushes or terminals 6 6 This reverse movement of the terminal support 'eT deenergizes the magnet of the calling circuit which corresponds to the magnet e of the device a, and the terminal support of the calling station is then automatically operated to connect the telephone of said calling station in metallic circuit with the line conductors or Wires leading therefrom.

As the actuating piece .6 of the called station is elevated, the arm 6 carried thereby is also .elevated but the shoulder upon the terminal support e holds said arm out of its position assumed when about to engage the arm (2 as presently described. When the terminals e e e are connected, a talkand the spring 6 automatically returns the terminal support e to its normal position for permitting the passage of a calling cur rent from the line conductor .or wire A through the magnet of the signal A to the ground, as previously pointed out. I 

